A Case Study of Integrated Modeling of Middle Eocene Reservoirs in Wadu and Paliyad Fields, Cambay Onland Basin, India

Goutam Chakraborty
EXCOM-BD-JV Group, New Delhi, ONGC India, New Delhi, India

The paper deals with a case study of integrated modeling of multiple clastic deltaic reservoirs developed within Middle Eocene Kalol Formation in Wadu and Paliyad fields, situated in the Ahmedabad tectonic block of NNW-SSE trending Cambay aborted rift, India.

Structurally, the Wadu and Paliyad fields exhibit NW-SE and NNW-SSE trending nosal features (high trends) respectively at Middle Eocene level shallowing towards NW. The structural relief and palaeo-tectonic analysis indicate that these high trends correspond to pre-existing basement high.

The hydrocarbon producing Kalol reservoirs viz. Kalol-X, IX, VII+VI, V and IV, as developed and designated from bottom to top, ranging from siltstones to fine to medium grained sandstones, exhibit an abrupt facies change laterally causing a variable fluid distribution pattern which often led in missing a target oriented success during exploration and development phases of these fields. The present study was initiated at that direction to generate viable models of aforesaid reservoirs integrating 3D seismic and attributes with drilled well, testing and production data. The envisaged reservoir models at different pay levels are validated recently by one exploratory well exhibiting the development of hydrocarbon bearing reservoirs in Kalol-X, IX, VI and VB pay units. The well data match very closely to the anticipated structural levels of respective pay zones and isopays as well.

This hydrocarbon find results in demarcating additional prospective areas for exploration of both new pools as well as delineation of existing ones in these pays. All the reservoirs are anticipated to have wider depositional limits than mapped earlier. Substantial increase in IOIP and IGIP has been proved when compared with the existing reservoir limits of respective pay units.

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